Rebalancing after 2 day pump failure

[Alcibiades]

Hi, TFP community!

I have a couple of pretty simple questions, but let me start with the results of my most recent test (using a Taylor fas-dpd kit:

• FC 2.8
• CC 0.4 (usually 0 or 0.1)
• PH 7.8 (tends to rise over time)
• TA 70 (stays constant)
• CH 375​
• CYA 70
• Salt 4100 (very strange—jumped from 3300 with no addition of salt)

My pump recently failed for 2 days, but a $40 capacitor brought it back to life. Following that event, I have three questions for the experts:

1. Since the pump was fixed three days ago, the salt level readings from my SWG have been strangely high—jumping from 3300-3500 before the pump failure to 4100 over the past few days. Any idea what may have caused that and how I should deal with it?
2. My SWG often doesn’t generate quite enough chlorine to hit the goals I see in Pool Math for salt pools. I run the cell at 70% for 12 hours a day. Is it reasonable in the sunny Virginia summer to up the cell to a higher percentage, or will I risk burning it out?
3. My PH levels tend to rise over time and settle at the high end of the recommended values (around 7.8). I’ve read in these forums that this can be common with SWGs. Any tips for minimizing the up-creep (and should I be struggling to keep the PH at a lower value if it likes to live around 7.8)?

Thanks so much in advance!

Alcibiades

—-Edit: I don’t see my signature, so here it is—

30K gal A&S in-ground plaster pool; JP PlusHP 2 HP pump; JP DEV 60 sq ft cartridge filter; FusionSoft 1400 SWG (mineral cartridge removed); Polaris 3900 Sport w/ PB4-60 booster pump; Heatwave AquaCal; JP 2444 valve actuator; iAqualink . . . and a "Wall Whale" for regular scrubbing!

 

[YippeeSkippy]

i wonder if a bit of power surge or something similar got to the SWG and *confused* it?? Do you test your water separate from the device reading? Salt test K-1766 is what you need.

Your pH of 7.8, with a TA of 70 if fine. You could try dropping the TA to 60, but it might not be worth the effort. Just keep an eye on it and if the pH hits 8, lower it.

SWGs have a finite lifespan in hours. Do you know what size your cell is rated for? It may be undersized?? Since you are already running it at 70%, try 80% and see what difference that makes. Remember you can always augment with liquid chlorine/plain bleach.

Maddie

Just checked... yeah... cell is slightly small. We always suggest getting cells 2x the pool volume. Your pool is big at 30k gallons but the cell is only rated for 40k gallons.

 

[mknauss]

Do not trust the salinity readout from your SWCG. Always best to have a salt test kit. Taylor K1766 is recommended.

It is very likely you need to up the chlorine generation. You are only adding 1.7 ppm FC to your pool at those settings. I would suggest doubling it for awhile. Run the pump 24 hours a day or up the SWCG to 100% with 18 hours run time.

pH of 7.8 is fine. Let it be.

 

[Alcibiades]

Maddie and mknaus, thank you! Taylor K1766 is on order and I’ve set the swg to run at a higher percentage for now (and I’ll continue to supplement with 10% bleach, as needed).

And thanks for the reassurance on the ph. I’ve been trying to keep all my numbers at a happy median between the low/high limits listed in pool school, but chasing 7.5 with this pool tends to mean a constant need for muriatic acid that isn’t doing anything useful.

Really appreciate the advice!